To enable memcg charged kernel memory allocations from nmi context,
consume_obj_stock() and refill_obj_stock() needs to be nmi safe. With
the simple in_nmi() check, take the slow path of the objcg charging
which handles the charging and memcg stats updates correctly for the nmi
context.
Signed-off-by: Shakeel Butt <shakeel.butt@xxxxxxxxx>
---
mm/memcontrol.c | 14 +++++++++++++-
1 file changed, 13 insertions(+), 1 deletion(-)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index bba549c1f18c..6cfa3550f300 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2965,6 +2965,9 @@ static bool consume_obj_stock(struct obj_cgroup *objcg, unsigned int nr_bytes,
unsigned long flags;
bool ret = false;
+ if (unlikely(in_nmi()))
+ return ret;
+
local_lock_irqsave(&obj_stock.lock, flags);
stock = this_cpu_ptr(&obj_stock);
@@ -3068,6 +3071,15 @@ static void refill_obj_stock(struct obj_cgroup *objcg, unsigned int nr_bytes,
unsigned long flags;
unsigned int nr_pages = 0;
+ if (unlikely(in_nmi())) {
+ if (pgdat)
+ __mod_objcg_mlstate(objcg, pgdat, idx, nr_bytes);
+ nr_pages = nr_bytes >> PAGE_SHIFT;
+ nr_bytes = nr_bytes & (PAGE_SIZE - 1);
+ atomic_add(nr_bytes, &objcg->nr_charged_bytes);
+ goto out;
+ }
+
local_lock_irqsave(&obj_stock.lock, flags);
stock = this_cpu_ptr(&obj_stock);
@@ -3091,7 +3103,7 @@ static void refill_obj_stock(struct obj_cgroup *objcg, unsigned int nr_bytes,
}
local_unlock_irqrestore(&obj_stock.lock, flags);
-
+out:
if (nr_pages)
obj_cgroup_uncharge_pages(objcg, nr_pages);
}
--
2.47.1
